A highly sensitive non-aggregation colorimetric sensor for the determination of I⁻ based on its catalytic effect on Fe³⁺ etching gold nanorods
2013
Liu, Jia-Ming | Jiao, Li | Cui, Ma-Lin | Lin, Li-Ping | Wang, Xin-Xing | Zheng, Zhi-Yong | Zhang, Li-Hong | Jiang, Shu-Lian
I⁻ could accelerate the selective etching along longitudinal direction of gold nanorods (AuNRs) induced by Fe³⁺ in HCl medium, which decreased the aspect ratio (length/width) of AuNRs, and thus the longitudinal surface plasmon resonance (LSPR) absorption peaks of AuNRs blue shifted (Δλ=λ₀−λ), the corresponding absorbance decreased (ΔA=A₀−A), and the color of the solution obviously changed. Therefore, a non-aggregation AuNRs colorimetric sensor for the detection of I⁻ was developed. The proposed colorimetric sensor is responsive, simple, selective and sensitive with the limit of quantization (LOQ) of 8.8×10⁻⁸M. The highly accurate sensor has been used to determine the content of I⁻ in table salt samples with the results consistent with those obtained by inductively coupled plasma-mass spectroscopy (ICP-MS). Moreover, the morphological changes of AuNRs during the etching procedure were characterized by high resolution transmission electron microscopy (HRTEM) and the sensing mechanism for I⁻ detection was also discussed.
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